--- doc/DString.3	2016-06-21 23:41:14.727184016 +0200
+++ doc/DString.3	2016-06-22 02:10:26.015556291 +0200
@@ -82,7 +82,8 @@
 specifies the number of bytes to append.
 \fBTcl_DStringAppend\fR returns a pointer to the characters of
 the new string.  The string can also be retrieved from the
-\fIstring\fR field of the Tcl_DString structure.
+\fIstring\fR field of the Tcl_DString structure. The memory region
+of \fIbytes\fR must not overlap with the string \fIfield\fR. 
 .PP
 \fBTcl_DStringAppendElement\fR is similar to \fBTcl_DStringAppend\fR
 except that it does not take a \fIlength\fR argument (it appends
@@ -96,7 +97,8 @@
 or the last two characters of the current string are
 .QW " {" ).
 \fBTcl_DStringAppendElement\fR returns a pointer to the
-characters of the new string.
+characters of the new string. The memory region of \fIelement\fR must not
+overlap with the string \fIfield\fR.
 .PP
 \fBTcl_DStringStartSublist\fR and \fBTcl_DStringEndSublist\fR can be
 used to create nested lists.
